Many people get this error when tucking in a pokemon using game snyc. It is due to the Complete Pokedex Cheat. If you activated this cheat and saved the game, then you must have completed the pokedex. The Pokemon Company knows when you used this cheat. If you are thinking why have you used this cheat and have no hope... THERE IS A FIX!!!!!!! Use r4cce and put in this cheat (usrcheat.dat) For Pokemon White: 94000130 FFFB0000 0223D1D0 00001803 D5000000 00000000 C0000000 00000131 D6000000 0223D1D4 D2000000 00000000 For Pokemon Black: 94000130 FFFB0000 0223D1B0 00001803 D5000000 00000000 C0000000 00000131 D6000000 0223D1B4 D2000000 00000000 In the game activate the cheat and press select. Now by this time your POKEDEX HAS NO POKEMON REGISTERED.DO NOT VIEW YOUR POKEDEX because if you do it will freeze. Now walk into grass and capture any type of pokemon. Save the game, and now you can play dream world!